JNTUH
JNTUH B.Tech IV DIGITAL SIGNAL PROCESSING Previous Question Paper (January/February - 2023 - R18)
i) Question paper consists of Part A, Part B.
ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions.
iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Obtain the frequency response of the system given by h(n) = bnu(n).
Answer
The frequency response H(ω) is the discrete-time Fourier transform of the impulse response h(n) = bnu(n). It is defined as:
This is a geometric series of the form ∑n=0∞ (be-jω)n, which converges to 1/(1 - be-jω) provided |be-jω| < 1, or |b| < 1. Thus, the frequency response is:
Find whether the signal defined by x[n] = [5(1/2)n + 4(1/3)n] u(n) is causal.
Answer
A discrete-time signal x[n] is defined as causal if x[n] = 0 for all n < 0. The given signal is x[n] = [5(1/2)n + 4(1/3)n] u(n), where u(n) is the unit step function defined as u(n) = 1 for n ≥ 0 and u(n) = 0 for n < 0.
Since the term u(n) acts as a multiplier, for any n < 0, u(n) = 0, which results in x[n] = 0. Because the signal is zero for all negative values of n, it satisfies the condition for causality. Therefore, the signal is causal.
What are the differences between Overlap Save method and Overlap Add method?
Answer
Sign in to view the complete answer paper.
How many multiplications are required to compute N point DFT using Radix-2 FFT?
Answer
Sign in to view the complete answer paper.
What is the advantage of designing IIR Filters using pole-zero plots?
Answer
Sign in to view the complete answer paper.
Obtain the transfer function of Butterworth filter for order N=4.
Answer
Sign in to view the complete answer paper.
What is the reason for FIR filter to be always stable?
Answer
Sign in to view the complete answer paper.
Show that the filter with h(n) = [-1, 0, 1] is a linear phase filter.
Answer
Sign in to view the complete answer paper.
What is zero padding? Does zero padding improve the frequency resolution in the spectral estimate?
Answer
Sign in to view the complete answer paper.
What is Overflow Noise?
Answer
Sign in to view the complete answer paper.
Part B
An LTI system is described by the differential equation y'(t) + 3y(t) = x(t). The initial conditions of y(0) = 2. Find the output y(t) for a unit step input.
Answer
Sign in to view the complete answer paper.
Explain how Continuous time signals are converted into discrete time signals graphically.
Answer
Sign in to view the complete answer paper.
Obtain the frequency response of y(n) - 2y(n-1) + (2/9)y(n-2) = x(n) - (3/5)x(n-1). Also discuss the properties of frequency response of discrete time system.
Answer
Sign in to view the complete answer paper.
Explain with block diagrams how sampling rate can be converted by a rational factor M/L in frequency domain.
Answer
Sign in to view the complete answer paper.
State and Prove i) Circular Shift of a Sequence ii) Complex Conjugate property of DFT.
Answer
Sign in to view the complete answer paper.
Find the output y[n] of a filter whose impulse response is h[n] = {1,1,1} and input signal x[n]={3,-1,0,1,3,2,0,1,2,1} using overlap save method.
Answer
Sign in to view the complete answer paper.
Two finite duration sequence are given by x(n) = sin(nπ/2) for n = 0,1,2,3 and h(n) = 2n for n = 0,1,2,3. Determine circular convolution using DFT & IDFT method.
Answer
Sign in to view the complete answer paper.
Determine IDFT of X(K)={6,-2,-2j,2,-2+2j} using DIT algorithm.
Answer
Sign in to view the complete answer paper.
The specifications of desired low pass filter is 0.7 ≤ |H(ω)| ≤ 1.0 ; 0 ≤ ω ≤ 0.2π and |H(ω)| ≤ 0.3 ; 0.6π ≤ ω ≤ π. Design a Chebyshev digital filter using impulse invariant Transformation.
Answer
Sign in to view the complete answer paper.
Describe any one procedure for digitizing the transfer function of an analog filter.
Answer
Sign in to view the complete answer paper.
Design a Butterworth high pass filter satisfying fp = 0.32 Hz; αp = 0.5dB and fs = 0.16 Hz; αs = 30dB; F=1Hz using Bilinear transformation method.
Answer
Sign in to view the complete answer paper.
Explain the design procedure of Chebyshev filter with necessary equations.
Answer
Sign in to view the complete answer paper.
Design an Ideal Low pass filter using Hanning Window with N=11 where H(ejω) = 1 for π/6 ≤ |ω| ≤ π/3 and 0 otherwise.
Answer
Sign in to view the complete answer paper.
Explain Frequency sampling method of designing FIR filters.
Answer
Sign in to view the complete answer paper.
Design an ideal band reject filter using Hamming window for the given frequency response (N=11) where Hd(ejω) = 1 for ω < π/3 and ω > 2π/3 and 0 otherwise.
Answer
Sign in to view the complete answer paper.
Describe the procedure for designing FIR filter using Windowing technique. Also elaborate about the different windows used for the design.
Answer
Sign in to view the complete answer paper.
Realize the first order transfer function H(z) = 1 / (1- az-1) and draw its quantization model. Find the steady state noise power due to product round off.
Answer
Sign in to view the complete answer paper.
Evaluate the frequency response of the system described by the system function H(z) = 1 / (1-0.5z-1).
Answer
Sign in to view the complete answer paper.
Obtain the realization of the following with minimum number of multipliers and Direct form I and also parallel form: H(z) = 1/3 + 1/4 z-1 + 3/2 z-2 + 5/6 z-3 + 6/4 z-4 + 1/3 z-5
Answer
Sign in to view the complete answer paper.